The Atom Interferometry Observatory Network (AION) is a collaboration of seven UK institutions working on interferometry with strontium atoms. Development work on high-flux atom sources, transport and cooling of atoms, composite pulse sequences and narrow-bandwidth laser systems will be conducted in a coordinated parallel program in five dedicated laser laboratories and tested in table-top apparatus. After testing, the aim is for these sub-systems to be integrated together in a 10 m tall atom interferometer at the chosen site. The AION collaboration is linked to the MAGIS-100 strontium interferometer project in the US (contributing to the interferometry detection and readout platform, including cameras and analysis). A long-term objective is to set up a network of large-baseline atom interferometers with capability of making sensitive searches for ultralight dark matter and gravitational wave detection (with future generations of instruments). Within AION, the team at KCL investigates the applications to fundamental theoretical physics. AION is funded by the Quantum Sensors for Fundamental Physics programme of the UK Research & Innovation (STFC & EPSRC), starting in 2021. The institutions are: Imperial College and Kings College, London; Universities of Birmingham, Cambridge, Liverpool, Oxford; and the Rutherford Appleton Lab.
The Atom Interferometry Observatory Network (AION) is a collaboration of seven UK institutions working on interferometry with strontium atoms. Development work on high-flux atom sources, transport and cooling of atoms, composite pulse sequences and narrow-bandwidth laser systems will be conducted in a coordinated parallel program in five dedicated laser laboratories and tested in table-top apparatus. After testing, the aim is for these sub-systems to be integrated together in a 10 m tall atom interferometer at the chosen site. The AION collaboration is linked to the MAGIS-100 strontium interferometer project in the US (contributing to the interferometry detection and readout platform, including cameras and analysis). A long-term objective is to set up a network of large-baseline atom interferometers with capability of making sensitive searches for ultralight dark matter and gravitational wave detection (with future generations of instruments). Within AION, the team at KCL investigates the applications to fundamental theoretical physics. AION is funded by the Quantum Sensors for Fundamental Physics programme of the UK Research & Innovation (STFC & EPSRC), starting in 2021. The institutions are: Imperial College and Kings College, London; Universities of Birmingham, Cambridge, Liverpool, Oxford; and the Rutherford Appleton Lab.
Advancing our knowledge of the universe increasingly relies on technologies capable of extremely precise measurement. Quantum sensors have emerged as promising tools for searching for new physics by pushing the boundaries of precision in measuring time, acceleration, and gravity. Two promising platforms are long-baseline atom interferometers and atomic clocks, both of which rely on cold atoms. This thesis lies at the intersection of cold-atom physics, quantum technology, and particle phenomenology. We report experimental progress from the AION project, a next-generation atom interferometer for the detection of ultra-light dark matter and mid-frequency gravitational waves. Within the collaboration, we present the first results from a red magneto-optical trap (MOT) for strontium-88 atoms. A seed–amplifier injection-locked laser system was developed to address the 1S0–3P1 transition at 689 nm, delivering 13.8 mW of light to the science chamber. Using this setup, we produced an atomic cloud at a temperature of (812 ± 4) nK in the narrowband red MOT, marking a critical milestone in the project. Secondly, the potential of next-generation atomic and molecular clocks in constraining theories that violate the weak equivalence principle (EP) is investigated. A search for variations in the electron–proton mass ratio is performed using publicly available data from UTC. A statistical framework is then developed to model clock noise and forecast sensitivity to signals arising in theories of dark matter, dark energy, unification, and other EP-violating scenarios, providing new and improved constraints. The framework is packaged into a tool that translates clock noise characteristics into constraints on fundamental physics theories. A preliminary study investigating the effect of data gaps in signal recovery shows that annual signals with amplitudes above 10⁻¹⁶ can be recovered even with up to 83% missing data.
Atom interferometers in which atoms are delocalized over macroscopic distances can provide excellent sensitivity for gravitational measurements. I will describe progress on the design and construction of a two-meter-tall strontium atomic fountain that aims to leverage such atom interferometers to search for new interactions beyond the standard model via tests of the gravitational inverse square law and to make a new measurement of Newton’s gravitational constant. Moreover, I will discuss progress on MAGIS-100, a 100-meter-tall atom interferometer being built at Fermilab to serve as a prototype gravitational wave detector in the 0.3 – 3 Hz range and to search for ultralight dark matter.
Atom interferometry is a maturing quantum technology which provides one of the most precise approaches to explore fundamental physics, e.g. to search for dark matter, and one day to observe gravitational waves in the frequency range from 10 mHz - 10 Hz. Standard atom interferometers use Bragg or Raman two-photon transitions for the coherent manipulation of matter waves. In a Michelson configuration for atom-aided gravitational waves detection, two orthogonal arms are built to reject laser noise, in the same way as optical interferometers. Atom interferometers utilizing an optical clock transition for coherent manipulation are less affected by the technical noise of the laser, and as a result that single baseline detectors become feasible.At LP2N, we are building a vertical gravity-gradiometer based on atom interferometry using strontium atoms probed on such a clock transition. The final experimental setup will implement a 6-meter tall atomic fountain to realize gradiometry with two or more separated atomic clouds.In my dissertation, I present the realization of the experimental setup in all its sub-systems, and the first experiments with atoms at millikelvin temperature obtained with the first cooling stage with blue light. The laser system for the second red cooling phase and for the coherent manipulation is ready; meanwhile, we realized a dual-frequency Zeeman slower that improves the atomic flux by a factor of six. We also present a study of an original scheme to achieve pulsed and fast light-atom interaction in a narrow-linewidth cavity by exploiting the Stark shift as a high bandwidth switch; this technique could open to the use of narrow-linewidth cavities – and notably their high power buildup - in several contexts, like atom interferometry and quantum information.
Atom interferometry represents a quantum leap in the technology for the ultra-precise monitoring of accelerations and rotations and, therefore, for all the science that relies on the latter quantities. These sensors evolved from a new kind of optics based on matter-waves rather than light-waves and might result in an advancement of the fundamental detection limits by several orders of magnitude. Matter-wave optics is still a young, but rapidly progressing science. The Space Atom Interferometer project (SAI), funded by the European Space Agency, in a multi-pronged approach aims to investigate both experimentally and theoretically the various aspects of placing atom interferometers in space: the equipment needs, the realistically expected performance limits and potential scientific applications in a micro-gravity environment considering all aspects of quantum, relativistic and metrological sciences. A drop-tower compatible prototype of a single-axis atom interferometry accelerometer is under construction. At the same time the team is studying new schemes, e.g. based on degenerate quantum gases as source for the interferometer. A drop-tower compatible atom interferometry acceleration sensor prototype has been designed, and the manufacturing of its subsystems has been started. A compact modular laser system for cooling and trapping rubidium atoms has been assembled. A compact Raman laser module, featuring outstandingly low phase noise, has been realized. Possible schemes to implement coherent atomic sources in the atom interferometer have been experimentally demonstrated.
We present the technical proposal for the Atom Interferometer CERN Experiment (AICE), a O(100) m vertical atom interferometer to be installed against the wall of the PX46 access shaft to the LHC. AICE is conceived as a versatile and flexible long-baseline atom-interferometry facility whose primary scientific goal is probing for bosonic ultralight dark matter (ULDM) in a mass range inaccessible to other experiments, with a secondary goal of pioneering the exploration of gravitational waves (GWs) with frequencies in the range ${\sim}$0.03-3 Hz as a pathfinder for future longer-baseline detectors. The initial configuration employs ultracold 87Sr atoms in a single-photon 698-nm interferometer with three shaft-based atom sources in a multi-source gradiometer geometry, supported by one surface reference source for laser stabilisation and diagnostics, to target scalar ULDM. Operation with 88Sr will give sensitivity to axion-like particles (ALPs), vector ULDM with B−L couplings and violation of the principle of equivalence, while a 171Yb upgrade will improve the sensitivity to B−L couplings and equivalence violations. Probing the Einstein equivalence principle (EP) and measuring α will proceed in parallel with the ULDM searches. A conceptual feasibility study and a detailed technical implementation study have established that PX46 is a uniquely mature and implementation-ready site, with no technical showstoppers. Completing site preparation works during LS3 would enable the subsequent installation and operation of AICE without impacting HL-LHC operations. The detector design builds on the VLBAI and MAGIS experiments and the AION-10 Technical Design Report, scaling the strontium gradiometer architecture to the $\sim$100 m baseline. AICE is endorsed by the TVLBAI Proto-Collaboration, comprising 57 institutions in 22 countries.
Atom interferometry is a quantum sensor technology that uses ultra-cold atoms placed in entangled quantum states to detect minute changes in local fields arising from gravitational waves and ultra-light dark matter. Their extreme sensitivity to accelerations has been demonstrated for measurements of Newton’s gravitation constant, tests of the Equivalence Principle, and measurement of local gravity gradients. The search for ultra-light dark matter and measurements of gravitational waves requires interferometer baselines greater than approximately 100 m. In understanding the fundamental systematics and backgrounds of these detectors, we have discovered that atmospheric and seismic effects, even though physically decoupled from the atoms which are in vacuum and free-fall, are still detectable by the quantum phase of the atoms. From a different perspective these “noise” sources are also interesting signals that we may be able to understand better with these sensor platforms leading to cross-disciplinary studies in Earth sciences.